Occupant detection systems that use an electrode located proximate to a seating surface to radiate an electric field and thereby detect occupant presence are known; see U.S. Pat. No. 7,876,106 issued to Hansen et al. Jan. 25, 2011. However, environmental conditions, such as humidity and moisture, may interfere with the occupant detection system's readings. For instance, humidity or moisture may cause reduced distinction or separation between ‘Allow airbag deployment’ and ‘Inhibit airbag deployment’ signal outputs required for an occupant detection system to meet the Federal Motor Vehicle Safety Standards 208 (FMVSS208). For example, some children or car seats could be mischaracterized as adults by an inadequate occupant detection system. For applications with a seat-heater present in the seat, driven shield layers may be required to increased separation between the ‘Allow’ and ‘Inhibit’ conditions. It has been suggested to add a separate humidity sensor to the system in order for the system to be able to determine humidity level and compensate accordingly. Unfortunately, such additional sensors undesirably increase the cost of the system.